Image forming apparatus

Abstract

To provide an image forming apparatus that can partition a fuser and a cartridge from each other, while preventing an increase in the size of the image forming apparatus.SOLUTION: An image forming apparatus according to the present invention comprises a body housing, a process unit PU, a fuser 80, and a film FM. The process unit PU forms a toner image on a sheet S to be conveyed. The fuser is located downstream of the process unit PU in a conveyance direction of the sheet S, and has a heating roller 81 and a pressure roller 82. The fuser 80 sandwiches, with the pressure roller 82 and the heating roller 81, the sheet S on which a toner image is formed by the process unit PU, and applies heat and pressure to the toner image to be fixed to the sheet S. The film FM is an elastically deformable film FM that is attached, at its upper end part, to the body housing between the fuser 80 and the process unit PU. The film FM extends downward from a portion above a paper feed area toward the paper feed area.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known an image forming apparatus having a heat insulating wall made of resin between a fixing unit and a process cartridge, which prevents the heat of the fixing unit from affecting the cartridge side (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-252944 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the case of a resin heat-insulating wall, for example, when replacing a fixing unit, a certain distance is required between the heat-insulating wall and the fixing unit so that the moving fixing unit does not interfere with the heat-insulating wall. Also, even if the fixing unit does not move, if the parts in the fixing unit are movable, a certain distance is required between the heat-insulating wall and the fixing unit so that the heat-insulating wall does not interfere with the fixing unit. As a result, there is a problem that the image forming apparatus becomes large.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus that is capable of separating the fixing unit and the cartridge while preventing the image forming apparatus from becoming large. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, an image forming apparatus according to the present invention includes a main body housing, a process unit, a fixing unit, and a film. The process unit has a cartridge containing toner, and forms a toner image on a sheet that is conveyed. The fixing unit is located downstream of the process unit in the sheet conveyance direction and has a heating rotor and a pressure rotor. The fixing unit sandwiches the sheet on which the toner image has been formed by the process unit between the pressure rotor and the heating rotor, and applies heat and pressure to fix the toner image to the sheet. The film has an upper end attached to the main body housing between the fixing unit and the process unit, and extends downward from above the paper passage area toward the paper passage area. The film is elastically deformable.

[0007] Since the film is elastically deformable, when the fixing device and the film come into contact with each other, the film deforms, allowing the fixing device to be positioned in the correct position, eliminating the need to unnecessarily increase the distance between the film and the fixing device.

[0008] The film may extend, in the width direction perpendicular to the sheet conveying direction, beyond the range through which a sheet of the maximum width on which the image forming apparatus can form an image passes.

[0009] The fixing unit may further include a heat source extending in a width direction perpendicular to the sheet conveying direction, and the film may extend beyond the heat source in the width direction.

[0010] The fixing unit may further include a shutter that opens and closes the opening through which the sheet enters. The lower end of the film may be located between the upper and lower ends of the shutter in the open state.

[0011] The shutter may be configured to rotate when moving from the closed state to the open state, and the shutter may come into contact with the film when rotating to push the film upstream in the sheet transport direction.

[0012] By deforming the film with the shutter, the image forming apparatus can be made smaller in size in the sheet conveyance direction than when the film and the shutter are disposed apart.

[0013] The heating rotor may have a roller that contacts the sheet, and the film may extend beyond the roller in the width direction perpendicular to the sheet conveyance direction.

[0014] The processing unit may have a drawer that is detachable from the main body housing, and the cartridge may be detachably attached to the drawer. The main body housing may have a shaft that engages with the drawer, and the lower end of the film may be located below the shaft.

[0015] The drawer may also have a first connector having a first electrical contact and a spring that biases the first electrical contact. The main body housing may have a second connector having a second electrical contact that comes into contact with the first connector, and that connects to the first connector when the spring is deformed. The film may be located below the second connector.

[0016] By positioning the film below the second connector, heat transfer from the fixing unit to the second connector can be suppressed.

[0017] The process unit may also include a photosensitive drum and a developing roller that supplies toner to the photosensitive drum. The lower end of the film may be located below the developing roller.

[0018] By positioning the lower end of the film below the developing roller, heat transfer from the fixing unit to the developing roller can be suppressed.

[0019] The main body housing may further include a first frame located above the fixing unit and a second frame assembled to the first frame. The second frame may have a hook on which the film is hung. The film may be sandwiched between the first frame and the second frame.

[0020] By sandwiching the film between the first frame and the second frame, the upper end side of the film can be held without flapping.

[0021] The first frame may also support a paper discharge roller located downstream of the fixing unit in the sheet transport direction, which discharges the sheet to the outside of the main body housing.

[0022] The process unit may also have a drawer that is detachable from the main body housing. The cartridge can be detachably attached to the drawer. The main body housing may have a shaft that engages with the drawer. The first frame may have an engagement portion that engages with the shaft. The film may be located between the engagement portion and the fixing unit.

[0023] The fixing unit may also have a shutter that opens and closes the opening through which the sheet enters, and an opening member that opens the shutter by contacting the shaft. The film may have a cutout in a portion corresponding to the opening member.

[0024] By cutting out the portion of the film corresponding to the opening member, the opening member can reliably come into contact with the shaft.

[0025] The heating rotor and the pressure rotor may form a fixing nip that sandwiches the sheet. The process unit may have a photosensitive drum and a transfer roller. The photosensitive drum and the transfer roller may form a drum transfer nip that sandwiches the sheet. The lower end of the film may be located above a line connecting the fixing nip and the drum transfer nip when viewed in the width direction perpendicular to the sheet conveyance direction. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide an image forming apparatus that can separate the fixing unit and the cartridge while suppressing an increase in size of the image forming apparatus. [Brief explanation of the drawings]

[0027] [Figure 1]1 is a cross-sectional view of an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the paper discharge frame disassembled into a first frame and a second frame. [Figure 3] FIG. [Figure 4] FIG. 2 is a diagram showing a comparison of the sizes of a heating roller and a film. [Figure 5] FIG. 2 is a perspective view showing a drum frame. [Figure 6] FIG. 2 is an enlarged view of the vicinity of the fixing unit in FIG. [Figure 7] FIG. 2 is a diagram illustrating a state in which the fixing unit is removed from the main body housing. [Figure 8] FIG. 4 is a cross-sectional view of the fixing unit with the shutter open. [Figure 9] FIG. 4 is a cross-sectional view of the fixing unit with the shutter closed. [Figure 10] FIG. [Figure 11] FIG. 2 is a perspective view showing a shutter unit. [Figure 12] FIG. 2 is a perspective view showing the shutter unit in an exploded state. [Figure 13] 10A is a perspective view showing the shutter in an exploded state, and FIG. 10B is a perspective view showing the other end of the first shutter in the first direction. [Figure 14] FIG. 4 is a perspective view showing the movement of the second shutter relative to the first shutter. [Figure 15] 12A and 12B are cross-sectional views taken along the line XX in FIG. 11, showing a state in which the opening member is positioned at the first position (a), a state in which the opening member is positioned between the first position and the second position (b), and a state in which the opening member is positioned at the second position (c). [Figure 16] FIG. 2 is a plan view of the shutter unit seen from above. [Figure 17] FIG. 2 is a diagram illustrating the relationship between a shaft, a process unit, and a fixing unit. DETAILED DESCRIPTION OF THE INVENTION

[0028] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, the image forming apparatus 1 includes a main body housing 10, a sheet supply unit 20, an image forming unit 30, and a sheet discharge unit 90.

[0029] In the drawings referred to, the first, second, third and fifth directions are indicated by arrows, and the other direction is indicated by no arrow. In this embodiment, the first direction is a direction along the axial direction of the heating roller 81. The first direction is also a direction along the width direction perpendicular to the conveying direction of the sheet S. The second direction is a direction perpendicular to the first direction. The second direction is along the vertical direction. The third direction is a direction perpendicular to the first direction and the second direction.

[0030] In this embodiment, one side in the first direction corresponds to the right side of the image forming apparatus 1. One side in the second direction corresponds to the lower side in the vertical direction. One side in the third direction corresponds to the rear side of the image forming apparatus 1. Therefore, a user operates the image forming apparatus 1 while positioned in front of the image forming apparatus 1, which is the other side in the third direction.

[0031] The main body housing 10 has a front cover 11, a discharge tray 12, and a rear cover 13. The front cover 11 opens and closes an opening on the front side of the main body housing 10. The rear cover 13 opens and closes an opening on the rear side of the main body housing 10. The main body housing 10 further includes a main body connector 300 .

[0032] The sheet supply unit 20 includes a sheet tray 21 and a supply mechanism 22. The sheet tray 21 stores sheets S such as paper. The supply mechanism 22 supplies the sheets S in the sheet tray 21 to the image forming unit 30.

[0033] The image forming section 30 includes an exposure device 40, a process section PU, a transfer unit 70, and a fixing device 80.

[0034] The exposure device 40 is located above the process unit PU. The exposure device 40 emits a light beam to expose the surface of the photosensitive drum 51.

[0035] The process unit PU is located between the sheet tray 21 and the exposure device 40. The process unit PU is detachable from the main body housing 10 through an opening in the main body housing 10 that is opened by opening the front cover 11. The process unit PU includes a drum unit 50 and a plurality of toner cartridges 60.

[0036] The drum unit 50 includes a plurality of photosensitive drums 51, a plurality of chargers 52 corresponding to the plurality of photosensitive drums 51, and a drum frame 53 as an example of a drawer.

[0037] The drum frame 53 supports the photosensitive drum 51 and the charger 52. The drum frame 53 is detachable from the main body casing 10. A toner cartridge 60 is detachably attached to the drum frame 53.

[0038] In this embodiment, when the drum unit 50 is attached to the main body housing 10, it moves along the third direction from the other side of the third direction to one side of the third direction relative to the main body housing 10, and then moves diagonally toward one side of the third direction and one side of the second direction. When the drum unit 50 is detached from the main body housing 10, it moves diagonally toward the other side of the third direction and the other side of the second direction relative to the main body housing 10, and then moves along the third direction from one side of the third direction to the other side.

[0039] In the following, the direction in which the drum unit 50 moves diagonally downward and rearward when the drum unit 50 is attached to the main body housing 10 and the direction in which the drum unit 50 moves diagonally upward and frontward when the drum unit 50 is removed from the main body housing 10 are referred to as the fifth direction. One of the fifth directions is the direction in which the drum unit 50 moves diagonally downward and rearward. The other of the fifth directions is the direction in which the drum unit 50 moves diagonally upward and frontward.

[0040] The plurality of toner cartridges 60 contain toner of different colors. Each toner cartridge 60 includes a developing roller 61, a supply roller 62, a layer thickness regulating blade 63, a toner containing section 64 that contains toner, and an agitator 65.

[0041] The agitator 65 agitates the toner in the toner storage unit 64. The agitator 65 supplies the toner to the supply roller 62. The supply roller 62 supplies the toner to the development roller 61. The layer thickness regulating blade 63 regulates the toner on the development roller 61 to a constant thickness.

[0042] The transfer unit 70 is located between the sheet tray 21 and the process section PU. The transfer unit 70 includes a drive roller 71, a driven roller 72, a conveyor belt 73, and multiple transfer rollers 74. The conveyor belt 73 is an endless belt for conveying the sheet S. The drive roller 71 and the driven roller 72 rotate the conveyor belt 73. The transfer roller 74 is located inside the conveyor belt 73. The transfer roller 74 sandwiches the conveyor belt 73 and the sheet S conveyed by the conveyor belt 73 between the transfer roller 74 and the photosensitive drum 51. At this time, the transfer roller 74 forms a drum transfer nip NP1 (see FIG. 6) between the transfer roller 74 and the photosensitive drum 51.

[0043] The fixing unit 80 is located downstream of the process unit PU in the conveying direction of the sheet S. The fixing unit 80 includes a heating roller 81 as an example of a heating rotor, and a pressure roller 82 as an example of a pressure rotor. The heating roller 81 heats the sheet S. Two heaters 81A are disposed within the heating roller 81 as heat sources. The heaters 81A are, for example, halogen heaters. The heaters 81A extend in the axial direction. The heating roller 81 rotates by receiving a driving force from a driving source (not shown). The heating roller 81 extends in the width direction perpendicular to the conveying direction of the sheet S.

[0044] The pressure roller 82 sandwiches the sheet S between itself and the heating roller 81. The pressure roller 82 rotates following the rotation of the pressure roller 82. The pressure roller 82 forms a fixing nip NP2 between itself and the heating roller 81.

[0045] The charger 52 charges the surface of the photosensitive drum 51. The exposure device 40 exposes the surface of the photosensitive drum 51 to light. As a result, an electrostatic latent image is formed on the photosensitive drum 51. The development roller 61 supplies toner to the photosensitive drum 51. As a result, a toner image is formed on the photosensitive drum 51.

[0046] The sheet supply unit 20 transports the sheet S between the photosensitive drum 51 and the transfer roller 74. The toner image on the photosensitive drum 51 is transferred to the sheet S. The sheet S with the transferred toner image is transported between the heating roller 81 and the pressure roller 82, where it is heated and pressurized. As a result, the fixing unit 80 fixes the toner image to the sheet S.

[0047] The sheet discharge section 90 has a conveying roller 91 and a discharge roller 92. The conveying roller 91 conveys the sheet S to the discharge roller 92. The discharge roller 92 discharges the sheet S onto the discharge tray 12.

[0048] As shown in FIGS. 2 and 4, the main body housing 10 further includes a first side frame 14, a second side frame 15, and a paper ejection frame 17.

[0049] The first side frame 14 and the second side frame 15 are positioned apart from each other in the first direction. The process unit PU, the fuser 80, and the paper discharge frame 17 are arranged between the first side frame 14 and the second side frame 15. The first side frame 14 and the second side frame 15 support the process unit PU, the fuser 80, and the paper discharge frame 17.

[0050] The paper discharge frame 17 is located above the fixing unit 80. The paper discharge frame 17 has a first frame 17A and a second frame 17B. The first frame 17A supports a paper discharge roller 91A that discharges the sheet S out of the main body housing 10. The paper discharge roller 91A is located downstream of the fixing unit 80 in the conveying direction of the sheet S. The second frame 17B is assembled to the first frame 17A from one side in the second direction. The second frame 17B has a hook HK on the other side in the third direction.

[0051] The image forming apparatus 1 further includes a film FM. The film FM is an elastically deformable film whose upper end is attached to the main body housing 10 between the fixing unit 80 and the process unit PU. Specifically, the film FM has a main body portion FMB, a pair of mounting holes FM1, a pair of notches FM3, and a bent portion FM5.

[0052] The main body portion FMB extends in a first direction and a second direction. The pair of assembly holes FM1 are located in the main body portion FMB and are spaced apart from each other in the first direction. The pair of notches FM3 have a shape recessed from the lower end FM2 of the main body portion FMB of the film FM toward the other side in the second direction, that is, upward. The bent portion FM5 extends from the upper end of the main body portion FMB toward one side in the third direction.

[0053] The film FM is hooked onto the hook HK by inserting the second frame 17B into the assembly hole FM1. When the film FM is hooked onto the hook HK, the bent portion FM5 is positioned above the end of the second frame 17B. Then, by assembling the second frame 17B to the first frame 17A, the bent portion FM5 of the film FM is sandwiched between the first frame 17A and the second frame 17B, as shown in FIGS. 3 and 6. The main body portion FMB of the film FM extends downward from above the paper passage area through which the sheet S passes toward the paper passage area.

[0054] 3, the first frame 17A further has an engaging portion 17C. The engaging portion 17C engages with a shaft 16 fixed to the main body housing 10. The film FM is located between the engaging portion 17C and the fixing unit 80.

[0055] Here, the shaft 16 is a member for positioning the process unit PU, with both ends fixed to the first side frame 14 and the second side frame 15. The shaft 16 extends in a first direction. When the process unit PU is attached to the main body housing 10, the shaft 16 comes into contact with the process unit PU to position it. More specifically, the shaft 16 engages with a notch 53A in the drum frame 53, as shown in FIG. 6.

[0056] 4, in the width direction perpendicular to the conveyance direction of the sheet S, i.e., the first direction, the film FM extends to the outside of the range WS through which the widest sheet S on which the image forming apparatus 1 can form an image passes. In other words, in the width direction, the range WS through which the widest sheet S passes is located inside the range WF in which the film FM is located.

[0057] The film FM extends in the width direction outward beyond the heating roller 81. That is, in the width direction, the range WR in which the heating roller 81 is located is located inside the range WF in which the film FM is located.

[0058] The film FM extends outward in the width direction beyond the heater 81A. That is, in the width direction, the range WH where the heater 81A is located is located inside the range WF where the film FM is located. Note that if the heater 81A is a halogen heater, the range where the heater 81A is located is the range where the glass tube of the heater 81A is located.

[0059] As shown in FIG. 5, the drum unit 50 further includes a drum memory 54 as a storage medium and a first connector C1.

[0060] The drum memory 54 is located on one side of the drum frame 53 in the first direction. The drum memory 54 stores information about the drum unit 50. The information about the drum unit 50 includes, for example, information about the photosensitive drum 51 and information about the lifespan of the drum unit 50. The information about the photosensitive drum 51 includes, for example, the manufacturing date and manufacturing location of the photosensitive drum 51, and the maximum number of rotations that can be used. The information about the lifespan of the drum unit 50 includes, for example, the cumulative number of rotations of the photosensitive drum 51 and the cumulative number of pages printed using the photosensitive drum 51.

[0061] The first connector C1 has an electrical contact surface 55 as a first electrical contact, a connector substrate 410, and a holder 420. The electrical contact surface 55 is located on the other side of the drum frame 53 in the first direction. The electrical contact surface 55 is electrically connected to the drum memory 54 by a cable (not shown).

[0062] When the drum unit 50 is attached to the main body housing 10, the first connector C1 is electrically connected to the main body connector 300. With the first connector C1 connected to the main body connector 300, the electrical contact surface 55 is in electrical contact with the main body electrode 310 (see FIG. 3) of the main body housing 10. When the drum unit 50 is attached to the main body housing 10 and the first connector C1 and the main body connector 300 are electrically connected, the control device (not shown) of the main body housing 10 can communicate with the drum memory 54.

[0063] The holder 420 holds the electrical contact surface 55. Specifically, the holder 420 holds a connector substrate 410 having electrodes 411. As shown in FIG. 6 , the holder 420 includes a first holder 430, a second holder 440, and a spring 450.

[0064] The first holder 430 holds the electrical contact surface 55. Specifically, the first holder 430 holds the connector substrate 410. Second holder 440 holds first holder 430. More specifically, second holder 440 holds first holder 430 so that it can move in the fourth direction. Second holder 440 holds first holder 430 so that it can move linearly in the fourth direction.

[0065] Spring 450 biases first holder 430 in the fourth direction in a direction in which electrical contact surface 55 moves away from second holder 440. Spring 450 is located between first holder 430 and second holder 440. As an example, spring 450 is a compression coil spring.

[0066] Returning to FIG. 3, the main body connector 300 as the second connector has a plurality of main body electrodes 310 as second electrical contacts, a first connector frame 320, and a second connector frame 330. The plurality of body electrodes 310 are aligned in a first direction. The body electrodes 310 are, for example, pogo pins.

[0067] The first connector frame 320 holds the main electrode 310 .

[0068] 6, the main body connector 300 is open toward the other side in the fifth direction. This allows the main body connector 300 to receive the first connector C1, which moves from the other side to the one side in the fifth direction when the drum unit 50 is attached to the main body housing 10.

[0069] The second connector frame 330 has a contact surface 331 and a guide surface 332 .

[0070] The contact surface 331 comes into contact with the second holder 440 of the first connector C1 when the drum unit 50 is attached to the main body casing 10. The contact surface 331 faces the main body electrode 310 in the fourth direction.

[0071] The fourth direction is a direction intersecting the electrical contact surface 55. In this embodiment, the fourth direction is a direction perpendicular to the electrical contact surface 55. More specifically, the fourth direction is a direction perpendicular to the electrical contact surface 55 when the drum unit 50 is attached to the main body housing 10 and the electrical contact surface 55 is in contact with the main body electrode 310.

[0072] The first connector C1 is located between the main electrode 310 and the contact surface 331 when the drum unit 50 is attached to the main housing 10. The contact surface 331 is perpendicular to the fourth direction.

[0073] The guide surface 332 guides the second holder 440 of the first connector C1 toward the contact surface 331 while the drum unit 50 is being attached to the main body housing 10. The guide surface 332 extends from the contact surface 331. The guide surface 332 is inclined with respect to the fourth direction. Specifically, the guide surface 332 is inclined such that the position of the guide surface 332 in the fourth direction becomes farther away from the main electrode 310 as the guide surface 332 moves away from the contact surface 331.

[0074] The second holder 440 has a holder end surface 441 and an inclined surface 442 . The holder end surface 441 comes into contact with the contact surface 331 of the main body connector 300 when the drum unit 50 is attached to the main body housing 10. The holder end surface 441 is the end surface of the second holder 440 that is farthest from the electrical contact surface 55 in the fourth direction.

[0075] The inclined surface 442 comes into contact with the guide surface 332 of the main body connector 300 while the drum unit 50 is being attached to the main body housing 10. The inclined surface 442 extends from the holder end surface 441. The inclined surface 442 is inclined with respect to the fourth direction. Specifically, the inclined surface 442 is inclined such that the position of the inclined surface 442 in the fourth direction approaches the electrical contact surface 55 as it moves away from the holder end surface 441.

[0076] When the drum unit 50 is attached to the main body housing 10, the electrical contact surface 55 is in contact with the main body electrode 310, and the holder end surface 441 is in contact with the contact surface 331, the spring 450 biases the first holder 430 toward the main body electrode 310. As a result, the restoring force of the spring 450 presses the electrical contact surface 55 against the main body electrode 310.

[0077] The film FM is located between the process unit PU and the fixing unit 80. More specifically, in the third direction, the film FM is located on one side of the process unit PU, and the fixing unit 80 is located on one side of the film FM. The lower end FM2 of the film FM is located below the developing roller 61 of the process unit PU.

[0078] When viewed from the width direction perpendicular to the conveying direction of the sheet S, the lower end FM2 of the film FM is located above a straight line LN connecting the center of the drum transfer nip NP1 and the center of the fixing nip NP2.

[0079] The lower end FM2 of the film FM is located below the shaft 16.

[0080] The lower end FM2 of the film FM is located below the lower end of the heating roller 81.

[0081] The film FM is located below the main connector 300 in the up-down direction.

[0082] 7, the fixing unit 80 is detachable from the main body housing 10 through an opening in the main body housing 10 that is opened by opening the rear cover 13. In other words, the main body housing 10 supports the fixing unit 80 in a detachable manner.

[0083] As shown in FIG. 8, the fixing unit 80 further includes a fixing housing 100 and a shutter unit 200.

[0084] The fixing housing 100 has an opening 101 through which the sheet S can pass. The opening 101 is an opening through which the sheet S passes from outside the fixing housing 100 to enter the fixing housing 100. The fixing housing 100 is detachable from the main body housing 10.

[0085] The shutter unit 200 is a mechanism for opening and closing the opening 101. The shutter unit 200 is switchable between an open state shown in Fig. 8 and a closed state shown in Fig. 9. When the shutter unit 200 is in the open state, it opens the opening 101. When the shutter unit 200 is in the closed state, it closes the opening 101.

[0086] It is sufficient that the shutter unit 200, when in the closed state, covers at least a part of the opening 101. More specifically, the shutter unit 200 only needs to cover the opening 101 to the extent that the user's fingers cannot enter the opening 101.

[0087] The film FM is located between the shutter unit 200 and the shaft 16. The lower end FM2 of the film FM is located between the upper end UL and the lower end LL of the shutter unit 200 in the open state shown in FIG.

[0088] 10 and 11, the shutter unit 200 includes a support member 210, two opening members 220, and a shutter 230. The support member 210, the two opening members 220, and the shutter 230 are made of resin or the like. As shown in FIG. 3, the film FM has a notch FM3 in a portion corresponding to the opening member 220. In the following description, when directions are explained, the first direction, second direction, and third direction shown in FIG. 10 are used.

[0089] The support member 210 supports the opening member 220 so as to be movable in the third direction. As shown in FIG.

[0090] As shown in FIG. 12, the support member 210 has an opposing portion 211, two support portions 212, a first wall 213, a second wall 214, and a third wall 215.

[0091] The facing portion 211 is a plate-shaped portion. The facing portion 211 has a surface perpendicular to the second direction. The facing portion 211 has a plurality of holes 211A. The holes 211A penetrate the facing portion 211 in the second direction, that is, the up-and-down direction.

[0092] The support portions 212 are portions for movably supporting the opening member 220. One of the two support portions 212 is located at one end of the facing portion 211 in the first direction. The other support portion 212 is located at the other end of the facing portion 211 in the first direction.

[0093] The support portion 212 protrudes further to the other side in the third direction than the facing portion 211. The support portion 212 has an elongated hole 212A that is long in the third direction.

[0094] The first wall 213 protrudes from one end of the opposing portion 211 and each of the support portions 212 in the third direction toward the other side in the second direction.

[0095] The second wall 214 is located at one end in the first direction of the first wall 213. The second wall 214 extends from the support portion 212 on one side in the first direction to the other side in the second direction. The support portion 212 on one side in the first direction is located between the opposing portion 211 and the second wall 214 in the first direction.

[0096] The third wall 215 is located at the other end in the first direction of the first wall 213. The third wall 215 extends from the support portion 212 on the other side in the first direction to the other side in the second direction. The support portion 212 on the other side in the first direction is located between the opposing portion 211 and the third wall 215 in the first direction.

[0097] The opening member 220 is movable between a first position shown in Fig. 9 and a second position shown in Fig. 8. The second position is a position where the opening member 220 is retracted further into the fixing housing 100 than the first position. When the opening member 220 is located at the first position, it protrudes from the outer surface 102 of the fixing housing 100.

[0098] 12, one opening member 220 is disposed at each of one end and the other end in the first direction of the shutter 230. Each of the two opening members 220 has a main body 221, a boss 222, and a leg 223. In the following description, the opening member 220 on one side in the first direction will also be referred to as the "first opening member 220A," and the opening member 220 on the other side in the first direction will also be referred to as the "second opening member 220B."

[0099] The main body portion 221 is a portion supported from below by the support portion 212 of the support member 210. The main body portion 221 has a first portion 221A and a second portion 221B. The first portion 221A is rectangular and tubular. The dimension of the first portion 221A in the third direction is larger than the dimensions in other directions. The second portion 221B covers an opening on one side of the first portion 221A in the third direction.

[0100] The boss 222 protrudes in the first direction from the main body 221 toward the shutter 230. The boss 222 supports the shutter 230 so that the shutter 230 is rotatable.

[0101] The leg portion 223 protrudes downward from the main body portion 221. The leg portion 233 is inserted into the elongated hole 212A of the support portion 212.

[0102] The first opening member 220A further has a spring hook portion 224. The spring hook portion 224 is a portion for hooking a shutter spring 260, which will be described later. The spring hook portion 224 is located on the surface of the main body portion 221 on the shutter 230 side.

[0103] 8 and 9, the shutter 230 is a member that opens and closes the opening 101 of the fixing housing 100. As shown in FIGS.

[0104] 15, the first shutter 240 is rotatably supported by each opening member 220. This allows the rotation axis AX of the first shutter 240 to move in the third direction together with each opening member 220. The second shutter 250 is rotatably supported by the first shutter 240.

[0105] The first shutter 240 can be switched between a first position shown in FIG. 15(a) and a second position shown in FIG. 15(c) by rotating. Specifically, the first shutter 240 opens by rotating in the order of FIGS. 15(a), (b), and (c). The first shutter 240 closes by rotating in the order of FIGS. 15(c), (b), and (a). The second shutter 250 rotates due to gravity as the first shutter 240 opens and closes. When the first shutter 240 is in the first position, it extends downward from the boss 222 of the opening member 220. When the first shutter 240 is in the second position, it extends from the boss 222 toward the other side in the third direction. When the first shutter 240 is in the second position, it is located above the opening 101 shown in FIG. 8.

[0106] The first shutter 240 is in the first position when the shutter 230 is closed, and in the second position when the shutter 230 is open.

[0107] As shown in FIG. 13, the first shutter 240 has a plate-shaped portion 241, a first side wall portion 242, a second side wall portion 243, and a spring hook portion 244.

[0108] The plate-shaped portion 241 is a plate-shaped portion whose dimension in a first direction is greater than the dimensions in other directions. The plate-shaped portion 241 has an outer surface 241A and a plurality of through-holes 241B.

[0109] 15(a), the outer surface 241A faces the other side in the third direction when the first shutter 240 is in the first position, that is, when the shutter 230 is closed. As shown in FIG. 15(c), the outer surface 241A faces upward when the first shutter 240 is in the second position, that is, when the shutter 230 is open.

[0110] 13, the through-hole 241B is a hole that penetrates the plate-shaped portion 241 in the third direction when the shutter 230 is closed. Therefore, when the shutter 230 is open, the through-hole 241B penetrates the plate-shaped portion 241 in the vertical direction.

[0111] The first side wall portion 242 is located at one end in the first direction of the plate-shaped portion 241. The first side wall portion 242 has a hole 242A that penetrates in the first direction. A part of the inner circumferential surface of the hole 242A is open in the third direction so that the first shutter 240 can be removed from the mold after injection molding.

[0112] The hole 242A is a hole into which the boss 222 of the first opening member 220A fits. The first side wall portion 242 of the first shutter 240 is rotatably supported by the boss 222 of the first opening member 220A.

[0113] 13(b), the second side wall portion 243 is located at the other end in the first direction of the plate-shaped portion 241. The second side wall portion 243 has a hole 243A that penetrates in the first direction. Note that a part of the inner circumferential surface of the hole 243A is open in the third direction so that the first shutter 240 can be removed from the mold after injection molding.

[0114] The hole 243A is a hole into which the boss 222 of the second opening member 220B fits. The second side wall portion 243 of the first shutter 240 is rotatably supported by the boss 222 of the second opening member 220B.

[0115] The spring hook portion 244 is a portion for hooking a shutter spring 260, which will be described later. The spring hook portion 244 is located on the first side wall portion 242.

[0116] As shown in FIG. 13( a ), the second shutter 250 has a plate-shaped portion 251 and two bosses 252 . The plate-shaped portion 241 is a plate-shaped portion whose dimension in a first direction is larger than the dimensions in other directions.

[0117] The bosses 252 are arranged one at each end in the first direction of the plate-shaped portion 241. Each boss 252 protrudes in the first direction from the plate-shaped portion 241. As shown in FIGS. 13 and 14 , each boss 252 is rotatably supported by the first side wall portion 242 and the second side wall portion 243 of the first shutter 240.

[0118] 15, the second shutter 250 is suspended from the first shutter 240. Regardless of the posture of the first shutter 240, the tip of the second shutter 250 faces downward due to gravity, so that the second shutter 250 is aligned substantially in the vertical direction.

[0119] 15(a), when the opening member 220 is located at the first position, the first shutter 240 is in a first posture in which the first shutter 240 is suspended from the opening member 220. In other words, when the opening member 220 is located at the first position, the shutter 230 is closed.

[0120] When the opening member 220 is located at the first position, the facing portion 211 of the support member 210 faces the first shutter 240 in the movement direction of the opening member 220, i.e., in the third direction. In this embodiment, when the opening member 220 is located at the first position, the facing portion 211 comes into contact with the first shutter 240. The facing portion 211 is located at a position away from the rotation axis AX of the first shutter 240 in the second direction orthogonal to the third direction. More specifically, the facing portion 211 is located below the rotation axis AX.

[0121] As a result, when the opening member 220 moves from the first position to the second position, the portion of the first shutter 240 below the rotation axis AX is pressed by the opposing portion 211, causing the first shutter 240 to rotate from the first position to the second position. In other words, in the process of the opening member 220 moving from the first position to the second position, the first shutter 240 is pressed by the opposing portion 211, causing the first shutter 240 to rotate and open the opening 101 of the fixing housing 100. Therefore, as shown in FIG. 15(c), when the opening member 220 is located at the second position, the shutter 230 is open.

[0122] As shown in FIGS. 15 and 16, the shutter unit 200 further includes a shutter spring 260 and two movement springs 270.

[0123] The shutter spring 260 is a spring that biases the shutter 230 in a direction that closes the shutter 230. In this embodiment, the shutter spring 260 is a torsion spring. The shutter spring 260 biases the first shutter 240 in a direction that rotates the first shutter 240 from the second position to the first position.

[0124] As shown in Figure 16, the shutter spring 260 is located between the first shutter 240 and the first opening member 220A. As shown in Figure 15, one end of the shutter spring 260 is hooked onto the spring hook portion 224 of the first opening member 220A.

[0125] The other end of the shutter spring 260 is hooked onto the spring hook portion 244 of the first shutter 240. The boss 222 of the first opening member 220A enters into and supports the coil portion of the shutter spring 260. The shutter spring 260 urges the first shutter 240 clockwise in the drawing so that the first shutter 240, which is in the second position shown in FIG. 15(c), is in the first position shown in FIG. 15(a).

[0126] 16, the moving spring 270 is a spring that biases the opening member 220 from the second position toward the first position. In this embodiment, the moving spring 270 is a compression coil spring.

[0127] In the following description, the moving spring 270 that biases the first opening member 220A will also be referred to as the "first moving spring 270A," and the moving spring 270 that biases the second opening member 220B will also be referred to as the "second moving spring 270B."

[0128] The first moving spring 270A is located between the first wall 213 of the support member 210 and the first opening member 220A. The second moving spring 270B is located between the first wall 213 of the support member 210 and the second opening member 220B.

[0129] 15(a) to 15(c), in this order, each opening member 220 moves from the first position to the second position by contacting and being pushed by the shaft 16. Since the film FM has a notch FM3 formed in a position corresponding to the opening member 220, the two opening members 220 pass through the notch FM3 and come into contact with the shaft 16 without coming into contact with the film FM. In the process of each opening member 220 moving from the first position to the second position, the first shutter 240 rotates from the first position to the second position. In other words, the opening member 220 opens the shutter 230 by contacting and being pushed by the shaft 16.

[0130] 17, when the fixing unit 80 is attached to the main body housing 10, the shaft 16 comes into contact with each opening member 220. The shaft 16 comes into contact with each opening member 220 and receives the biasing force of each moving spring 270. By coming into contact with each opening member 220, the shaft 16 holds each opening member 220 in the second position. At this time, each moving spring 270 biases each opening member 220 toward the other side in the third direction.

[0131] 15(c) to 15(a), each opening member 220 moves in a direction away from the shaft 16, and is thereby moved from the second position to the first position by the biasing force of each moving spring 270. In the process of each opening member 220 moving from the second position to the first position, the first shutter 240 rotates from the second position to the first position by the biasing force of the shutter spring 260. The opening member 220 moves from the second position to the first position while abutting against the shaft 16, thereby closing the shutter 230.

[0132] When the fixing device 80 is attached, a part of the film FM is located at a position corresponding to the shutter 230. When the shutter 230 rotates from the closed state shown in Fig. 15(a) to the open state shown in Fig. 15(c), the shutter 230 comes into contact with the film FM and pushes the film FM toward the other side in the third direction, which is upstream in the conveyance direction of the sheet S.

[0133] As described above, the following effects can be obtained in this embodiment.

[0134] Since the film FM is elastically deformable, when the fixing device 80 and the film FM come into contact with each other, the fixing device 80 can be positioned in the correct position by the deformation of the film FM, so there is no need to unnecessarily widen the distance between the film FM and the fixing device 80.

[0135] By deforming the film FM by the shutter 230, the image forming apparatus 1 can be made smaller in size in the conveyance direction of the sheet S than when the film FM and the shutter 230 are disposed apart from each other.

[0136] By positioning the film FM below the main body connector 300, heat transfer from the fixing unit 80 to the main body connector 300 can be suppressed.

[0137] By positioning the lower end FM2 of the film FM below the developing roller 61, the transfer of heat from the fixing device 80 to the developing roller 61 can be suppressed.

[0138] By sandwiching the film FM between the first frame 17A and the second frame 17B, the upper end side of the film FM can be held without flapping.

[0139] By providing the notch FM3 in the portion of the film FM that corresponds to the opening member 220, the opening member 220 can be reliably brought into contact with the shaft 16.

[0140] The present invention is not limited to the above-described embodiment, but can be used in various forms as exemplified below.

[0141] In the above-described embodiment, the spring 450 is a compression coil spring, but the spring 450 may be, for example, a wire spring, a leaf spring, or the like.

[0142] The heating rotor is not limited to a heating roller, but may be, for example, a ceramic heater, or may be configured to include a belt, a nip plate that contacts the inner surface of the belt, and a heat source that heats the belt and nip plate.

[0143] The pressure rotating body is not limited to a pressure roller, but may be configured to include, for example, a belt and a rubber pad disposed inside the belt.

[0144] In the above embodiment, a halogen heater is used as an example of a heat source, but the present invention is not limited to this and may be, for example, a heating resistor or an IH heat source. Here, an IH heat source refers to a device that does not generate heat itself but heats a roller or metal belt using electromagnetic induction heating.

[0145] The number of opening members may be one or three or more. When there is one opening member, the opening member may be located at the center of the shutter in the first direction.

[0146] The opening member may not protrude from the outer surface of the fixing housing when located at the first position, and may or may not protrude from the outer surface of the fixing housing when located at the second position.

[0147] The film may not have a cutout at the portion corresponding to the opening member. In this case, the film may be sandwiched between the shaft and the opening member when the opening member comes into contact with the shaft.

[0148] The shutter may be opened and closed in conjunction with the opening and closing of the cover of the main body housing. For example, a linkage mechanism that moves in conjunction with the opening and closing of the cover may be configured to push the opening member from the first position to the second position.

[0149] The elements described in the above-described embodiment and modified examples may be implemented in any combination. [Explanation of symbols]

[0150] 1. Image forming device 10 Main unit housing 60 Toner Cartridges 80 Fixing unit 81 Heating roller 82 Pressure roller PU Process Unit S seat

Claims

1. A main body housing; a process unit having a cartridge containing toner and forming a toner image on a conveyed sheet; a fixing unit located downstream of the process unit in the sheet conveyance direction, the fixing unit having a heating rotor and a pressure rotor, and sandwiching the sheet on which the toner image has been formed by the process unit between the pressure rotor and the heating rotor, and applying heat and pressure to fix the toner image to the sheet; an elastically deformable film whose upper end is attached to the main body housing between the fixing unit and the process unit, the film extending downward from above the paper passing area toward the paper passing area; An image forming apparatus comprising:

2. 2. The image forming apparatus according to claim 1, wherein the film extends in a width direction perpendicular to the sheet transport direction to outside the range through which a sheet of the maximum width on which the image forming apparatus can form an image passes.

3. 2. The image forming apparatus according to claim 1, wherein the fixing unit has a heat source extending in a width direction perpendicular to a sheet conveying direction, and the film extends beyond the heat source in the width direction.

4. the fixing unit has a shutter that opens and closes an opening through which the sheet enters, 2. An image forming apparatus according to claim 1, wherein the lower end of the film is located between the upper and lower ends of the shutter in an open state.

5. 5. The image forming apparatus according to claim 4, wherein the shutter is configured to rotate when moving from a closed state to an open state, and when rotating, the shutter abuts against the film and pushes the film upstream in the sheet transport direction.

6. 2. The image forming apparatus according to claim 1, wherein the heating rotator has a roller that contacts the sheet, and the film extends beyond the roller in a width direction perpendicular to a conveying direction of the sheet.

7. the process unit has a drawer that is detachable from the main body housing and into which the cartridge can be attached, the main body housing has a shaft that engages with the drawer, 2. The image forming apparatus according to claim 1, wherein the lower end of the film is positioned below the shaft.

8. the drawer has a first connector having a first electrical contact and a spring that biases the first electrical contact; the main body housing includes a second connector having a second electrical contact that contacts the first connector, the second connector being connected to the first connector in a state in which the spring is deformed; 8. The image forming apparatus according to claim 7, wherein the film is located below the second connector.

9. the process unit has a photosensitive drum and a developing roller that supplies toner to the photosensitive drum, 2. The image forming apparatus according to claim 1, wherein the lower end of the film is located below the developing roller.

10. The main body housing includes: a first frame positioned above the fixing unit; a second frame assembled to the first frame, the second frame has a hook to which the film is hooked, 2. The image forming apparatus according to claim 1, wherein the film is sandwiched between the first frame and the second frame.

11. 11. The image forming apparatus according to claim 10, wherein the first frame supports a paper discharge roller located downstream of the fixing unit in the sheet transport direction, the paper discharge roller discharging the sheet outside the main body housing.

12. the process unit has a drawer that is detachable from the main body housing and into which the cartridge can be attached, the main body housing has a shaft that engages with the drawer, the first frame has an engaging portion that engages with the shaft, 11. The image forming apparatus according to claim 10, wherein the film is positioned between the engagement portion and the fixing unit.

13. The fixing device is a shutter that opens and closes an opening through which the sheet enters; an opening member that opens the shutter by contacting the shaft, 13. The image forming apparatus according to claim 12, wherein the film has a cutout at a portion corresponding to the opening member.

14. the heating rotary member and the pressure rotary member form a fixing nip that sandwiches a sheet; the process unit has a photosensitive drum and a transfer roller, and the photosensitive drum and the transfer roller form a drum transfer nip that sandwiches a sheet; 2. The image forming apparatus according to claim 1, wherein the lower end of the film is located above a line connecting the fixing nip and the drum transfer nip when viewed in a width direction perpendicular to the sheet conveying direction.

Images